Quality Control Definition:

When a product is being manufactured in quantity
it is necessary to ensure that each item is up to
the specified quality. In order to keep a check on
this standard it is common to introduce a
statistical method of quality control which relies
on the taking of random samples from the production
line and subjecting them to intense scrutiny. The
results of such tests (allowing for a predetermined
margin of failure) will determine whether or not the
total output is of an acceptable quality.